1. Field of the Invention
This invention relates to an ink jet recording apparatus to be employed for copying device, facsimile, word processor, video output printer, output printer of computer, etc., particularly to a constitution for mounting a recording head equipped integrally with an ink tank for containing ink freely detachably onto the carriage as the recording head mounting means.
2. Related Background Art
Of the ink jet recording apparatus, there has been known devices such as those using an ink jet recording head, which can be a disposable head comprising internally an integrated combination of an ink tank for housing ink which is are recording medium and a recording head element having the function of discharging ink (hereinafter called recording head or ink jet recording head cartridge).
Examples of the mounting methods of such recording heads are described in U.S. Pat. No 4,599,625 (Terasawa et al), U.S. Pat. No. 4,630,078 (Watanabe), U.S. Pat. No. 4,633,274 (Matsuda), U.S. Pat. No. 4,635,080 (Watanabe), U.S. Pat. No. 4,712,172 (Kiyohara et al), U.S. Pat. No. 4,727,384 (Tsuda), etc.
In mounting such a recording head onto the carriage on the main body side of the recording device, since recording must be performed by attaching ink accurately to the proper position on the recording paper, and the connecting terminal for transmitting recording signals must be properly oriented, it has been required to fix and mount the recording head at a proper position.
To classify broadly the mounting methods of recording heads, there may be included the methods in which the ink cartridge is mounted from above or behind of the carriage in parallel or by simple rotation.
As an example which performs mounting simply, there is such constitution as shown in FIG. 1; 101 is a recording head of the type integrated with an ink tank, having a connecting terminal 101a having a plurality of electrical pads 111 and a discharge port surface of the ink recording head element 101c provided at the bottom. The carriage 102 is provided with a connecting terminal 102a for transmitting recording signals to the recording head. Here, 102a is constituted of a plurality of electrical pads 112 and 104 is a guide shaft for guiding movement of the carriage 102. Thus, when the recording head is mounted from above the carriage, attachment and detachment can be done very easily, but since the connecting terminals 101a and 102a are not rubbed against each other during mounting and therefore, if there is a coating or foreign matter due to ink contamination interposed between the connecting terminals, defective connections sometimes occur. Also, an unused recording head may sometimes have a very thin insulating protective film 121 provided for protection of connecting terminals. Then, in the case of such mounting method, there is no action ensuring connection by scraping off the protective film. Therefore, this example could never be said to be the optimum example of the connecting method of signal terminals. Also, in commencing use after mounting an unused recording head, it is necessary to form immediately the state where ink can be satisfactorily discharged by means of a discharge recovery means, etc.
Accordingly, the present invention entails attaching and detaching the recording head at the home position which becomes the waiting position of the recording head, and protecting the discharge port preferably on completion of mounting of the recording head.
FIG. 2A, as an example based on the above thought, mounts a recording head from behind the carriage. Similarly as in FIG. 1, 101 is the recording head and 102 is the carriage. Here, 103 is a discharge recovery device equipped with a cap for protecting the discharge port of the recording head and preventing ink fixing. The constitution is such that, by performing mounting of the recording head by inserting the recording head 101 from behind the carriage 102 in the direction of the arrowhead, the recording head 101 is capped at the fixed position, and the connecting terminals 101a and 102a are correctly connected. However, according to such method, the connecting terminals will be respectively rubbed during mounting successively. Particularly, the electrode pad 101 of the connecting terminal of the recording head located on the discharging port side will be rubbed with all the electrode pads of the carriage 102. Therefore, a part of all of the terminals will be considerably damaged, whereby it has been found that electrical signals cannot be transmitted, thus causing defective discharging.
Accordingly, the present inventors have further thought of a method of mounting by rotation of the recording head 101 as shown in FIG. 2B, but with such constitution, mounting must be done with the discharge port surface 101b which becomes the front surface of the recording head 101, particularly the upper part of 101b, being positioned greatly forward before the constant position after mounting. Then, a great space is required in front of the carriage. However, when good ink discharging is considered, since the interval between the recording head and the recording paper is designed to be 3.0 mm or less, and therefore it has been found to be difficult to take such constitution. Also, even if mounting may be effected at the home position, because great mutual interference with the cap cannot be avoided, such inconvenience as deformation of cap, etc. have been found to occur.